Publications by authors named "Naoya Katsumi"

Marine plastic pollution has highlighted the need to address the disposal of plastic materials used in agricultural fields and prevent their runoff. To assess the status of microplastics derived from polymer-coated fertilizers (microcapsules), we investigated their seasonal and daily variations in a small agricultural river in Ishikawa Prefecture, Japan, throughout the irrigation period of April to October 2021 and 2022. We also investigated the relationship between microcapsule concentration and water quality.

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The purpose of this study was to identify a method to accurately separate small microplastics (<100 μm) from soil and sediment. We initially conducted spike-and-recovery tests using polyethylene microbeads and density separation and found that the recovery rate of microplastic particles smaller than 100 μm was less than 60%. This result suggested that previous reports have underestimated the concentrations of microplastics smaller than 100 μm in soil.

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The concentrations of polycyclic aromatic hydrocarbons (PAHs) in aerosol were measured in Shinjuku, which is central Tokyo, Japan, for 10 years from 2007 to 2016. The effects of changes in emission sources and their degradation by reaction with ozone were assessed in this study. There was no significant increasing or decreasing trend of the PAH concentrations during 10 years (P > 0.

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Polymer-based microcapsules derived from coated fertilizers are not recovered after use. Therefore, they are a source of microplastics to the agricultural lands and coastal areas of Japan. In this study, we investigated the input-output balance of microcapsules in three paddy fields and the timing of microcapsule discharge from the fields with the aim of developing effective techniques to reduce microcapsule discharge.

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Japanese agriculture uses large amounts of plastics. Fertilizer-containing plastic microcapsules with a diameter of 2-5 mm ("coated fertilizer") are not recovered after use, and after diffusion of the fertilizer components these microcapsules are found in large quantities, not only on agricultural land but also along the coast of Japan. Here, we investigated the accumulation of microcapsules derived from coated fertilizer in 19 paddy fields.

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Fixed-point and multi-point field survey was conducted to determine the actual contamination of the Japanese coast by microcapsules derived from coated fertilizers. The results indicated that the amount of microcapsules increased during the irrigation season (9423-74,869 pieces/m) and decreased in the non-irrigation season (77-1471 pieces/m). Microcapsules accounted for 90% of all microplastics sampled during the irrigation season.

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Background: Bile acid-binding agents, such as cholestyramine and colesevelam, improve both cholesterol and glucose metabolism. Kaki-tannin, a polymerized condensed tannin derived from persimmon (Diospyros kaki), has been shown to have bile acid-binding capacity and a hypocholesterolemic effect. However, its effects on glucose metabolism have not been well studied, and the binding selectivity of kaki-tannin to bile acid molecules has not been reported.

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We investigated the physicochemical properties of starches extracted from Vigna angularis variants Noto-dainagon, Kyoto-dainagon, dainagon, and erimo-type adzuki beans. The particle size was larger in the Noto-dainagon starch than in the other starches, but all starches displayed a C-type crystal structure in the X-ray diffraction analysis. The onset and peak temperatures of gelatinization were approximately 7 °C lower in the Noto-dainagon and Kyoto-dainagon starches than in the dainagon and adzuki bean starches.

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We investigated the physicochemical properties of starches extracted from 8 lotus ( Gaertn.) rhizomes harvested in different months (September 2012 to May 2013). The physicochemical properties of the lotus starches depended on the harvest date.

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We investigated the physicochemical properties of starches from rhizomes of two lotus ( Gaertn.) cultivars, Shinashirobana cultivar and Kanasumi-line No. 20, harvested at the same farm in Japan.

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Evolved gas analysis-mass spectrometry (EGA-MS) provides a direct connection between the pyrolyzer and mass spectrometer through a deactivated capillary tube, and provides both a thermal profile relating to the differential thermogravimetric curve of the sample and a mass spectrum of evolved gas from the sample. In this study, EGA-MS was performed to obtain thermal profiles and identify the pyrolysis products of 12 humic acids (HAs) with different degrees of humification extracted from 5 Andisols, 3 Entisols, and 3 Inceptisols, as well as soil samples. All HAs were thermally decomposed gradually over a wide temperature range (100-700°C), and the EGA curves showed four peaks and shoulders at around 250, 350, 450, and 550°C.

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Wildfires and prescribed burning can affect both the quality and the quantity of organic matter in soils. In this study, we investigated qualitative and quantitative changes of soil humic substances in two different soils (an Entisol from a paddy field and an Inceptisol from a cedar forest) under several controlled heating conditions. Soil samples were heated in a muffle furnace at 200, 250, or 300 °C for 1, 3, 5, or 12h.

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Endophytic nitrogen-fixing organisms have been isolated from the aerial parts of field-grown sweet potato (Ipomoea batatas). The (15)N dilution method, which is based on the differences in stable nitrogen isotope ratios, is useful for measuring nitrogen fixation in the field. In this study, seedlings of two sweet potato cultivars, 'Beniazuma' and 'Benikomachi,' were transplanted into an alluvial soil that had been treated with organic improving material in advance.

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Recently, the use of non-steroidal anti-inflammatory drug(NSAID) as an anti-inflammatory analgesic and antithrombotic has increased with the general aging of our society. Although it is understood that gastric mucosal injury is most-frequent side-effect of NSAID, there are actually a variety of mechanisms that NSAID has, some which are due to the depressed production of prostaglandin (PG). The main action of PG in the gastric mucosa is the regulation of gastric mucosa protecting mechanism and if PG is insufficient, the gastric mucosa is weakened.

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Endoscopic injection sclerotherapy (EIS) is conducted to treat esophageal varices associated with liver cirrhosis. Cirrhotic patients have protein energy malnutrition (PEM), and their malnutrition is aggravated during EIS due to dietary restrictions. The aim of this study was to evaluate the dietetic benefits of oral branched chain amino acid-rich nutrient (BCAA-rich nutrient) administered during EIS.

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Background And Aims: Self-expandable metal stents (SEMS) for malignant biliary strictures sometimes occlude, requiring the insertion of another stent. When a guide wire is advanced conventionally through the proximal portion of an occluded SEMS, the guide wire sometimes penetrates the stent mesh. The present study reports a new guide wire insertion technique that prevents this problem from occurring.

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Background: Dieulafoy's lesion is an important cause of GI bleeding. The results of hemoclip application as the first treatment of choice for Dieulafoy's lesions have not been reported. This study prospectively examined the short- and long-term outcomes of hemoclip application for Dieulafoy's lesions.

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Background And Aim: Recently, the number of peptic ulcer patients aged 80 years or older has been increasing. However, little information is available concerning therapeutic endoscopy for these patients. The objective of this study was to evaluate the efficacy of endoscopic hemostasis for peptic ulcer bleeding in patients aged 80 years or older.

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